TABLES OF TOE GROUPS. 43 



BASE OF THE SECTION IN THE GRAND CANON OF THE 



COLORADO. 



I Base of Red Wall Group. 



Sandstones and shales, with a lew limestones ; uncon- 

 formable by extensive plication and erosion on the 

 next. 



Sandstones, shales, and a few limestones. On further 

 study this group will probably bo subdivided. 



Ilornl'lendic and micaceous schists and slates, -with 

 beds and dikes of granite. Thickness unknown. 

 Found at the bottom of the Grand Canon. 



